A liquid crystal display enjoys a lighter weight and smaller size than a display using a cathode ray tube, and thus it is conveniently portable. Further, it has the advantage of not radiating an electromagnetic wave which is considered harmful to humans. Therefore, the liquid crystal display is widely used for small displays (e.g., of an electronic calculator) and large displays (e.g., of a notebook computer).
A structure of the conventional liquid crystal display panel is shown in FIG. 1. Referring to FIG. 1, a process for manufacturing such a liquid crystal display panel will be described.
Black matrixes 15 are formed on a glass substrate 11, and a red filter 16, a green filter 17, and a blue filter 18 are, respectively, formed between the black matrixes 15. The combination of the black matrixes 15, red filter 16, green filter 17, and blue filter 18 is commonly referred to as a color filter layer. To planarize the color filter layer and to enhance chemical resistance, a protective film 13 is formed thereon, and an indium-tin oxide (ITO) electrode layer 14 is then formed on the protective layer 13.
When forming the red, green, and blue filters, a red coloring resin composition is first coated on the whole surface of the substrate 11 having black matrixes 15 formed therein, which is exposed through a photo mask and then developed, to produce the red filter 16. The above procedure is repeated for green and blue, which produces, respectively, the green and blue filters 17 and 18.
A general photosensitive coloring resin composition includes a binding resin, pigments, a dispersing agent, a photo-polymerizable monomer, a photo-polymerization initiator, dilution solvents and additives. Such photosensitive coloring resin composition can be obtained according to the following procedure.
First, binding resin and pigment are mixed with dispersing agent, such that the pigment is sufficiently dispersed into the resin. Then, the photo-polymerizable monomer and photo-polymerization initiator are added, to form a mixture. Finally, the mixture is diluted with solvent, to form a photosensitive coloring resin composition.
When a liquid crystal display panel is manufactured by the above procedure, since the coloring resin composition is coated on the whole surface of the substrate, the coloring resin composition is used for an undesired portion of the substrate, thus, greatly lowering the utility of a material. Also, in the photosensitive coloring resin composition for the color filter, since the ratio of photosensitizer and bonding resin amounts to more than 50%, the ratio of pigment is rather low.
On the other hand, the protective film is generally disposed between the color filter layer and ITO electrode layer. Before and after the protective film formation, a grinding process in which the whole surface of the substrate is planarized should be accomplished.
As above, the process for manufacturing the conventional liquid crystal display panel is complicated, and the thus-obtained liquid crystal display panel has a narrow color reproduction range and poor color characteristics.